In recent years, there has been a dramatic increase in the demand for propylene to feed the growing markets for polypropylene, propylene oxide and acrylic acid. Currently, most of the propylene produced worldwide (74 million tons/year) is a by-product from steam cracking units (57%) which primarily produce ethylene, or a by-product from Fluid Catalytic Cracking (FCC) units (30%) which primarily produce gasoline. These processes cannot respond adequately to a rapid increase in propylene demand.
Other propylene production processes contribute about 12% of total propylene production. Among these processes are propane dehydrogenation (PDH), metathesis reactions requiring both ethylene and butene, high severity FCC, olefins cracking and methanol to olefins (MTO). However, propylene demand has exceeded ethylene and gasoline/distillate demand, and propylene supply has not kept pace with this increase in propylene demand.